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Re: X-Ray HT power supply
Tesla List wrote:
> Original Poster: Gavin Hubbard <ghub005-at-xtra.co.nz>
>
> Hello all.
>
> This morning a local radiology technician (who knows of my HV interests)
> 'gifted' me a 150kV, 500mA (peak) x-ray HT power supply. The power supply
> is operational and comes from a decommissioned installation. The output is
> full wave rectified (approx 2-3% ripple at peak current) and the only fault
> with the unit is that the tube filament heater output (6V above 150kV) is
> not functional.
>
> I would be interested if anyone on this list has designed or built a TC
> which is powered by such an extremely high DC tank voltage. I have been
> playing with the numbers today, and am aware that such a coil will require
> a physically huge primary capacitor (approx 130 litres of oil dielectric)
> and that the whole tank circuit and secondary would have to be run under
> oil (except the spark gap of course). I would also be interested to know
> what other inherent problems are to be expected with these designs.
>
> Thanks in advance for your help,
>
> Gavin Hubbard
An interesting idea, to run the secondary under oil; what containment are you
contemplating?
As you're probably aware the filament circuit is a separate circuit coming off
of the autotransformer, a patch or substitute should be achievable if needed,
I intend to use the filament circuit in a similar unit to heat the tetrode
filaments in a tube TC. But if your planning to use a SG you'll have to do
some very serious quenching or go to either alternate atmosphere or stimulated
discharge gap technology at this voltage; at least that seem to be the case
from the posts; any dissenting opinions? Klystrons or other HV tubes are
another thought.
There seem to be so many different ways to pump the tank circuit, that I am
still debating removing the rectification on the tube side of the 3 phase
transformer and using the AC output instead of DC. It would be possible to tap
a smaller tank onto each of the 3 phases; but synchronizing the tanks would be
a nightmare, I'd imagine. Somebody mentioned that the TCBOR had done it
though. I have been trying to review the old archives but there are lots of
them and time is so limited.
The use of AC vs DC at the cap seems to be a point worthy of discussion, but
I'm sure it has been rehashed many times before my arrival. If it isn't too
basic or too many times revisited; is DC or AC to the tank preferable at these
voltages? Does it depend on the cap only?
Bryan Kaufman